Seat system with inflatable section within an outer belt section and method of restraint

ABSTRACT

An inflatable belt system and method of operation for a vehicle occupant restraint in which a lap belt section or torso belt section or both have dual load bearing portions with an inner portion being inflatable. During inflation of the inner portion the other outer belt portion ruptures along a frangible line. The outer belt portion is a woven cylindrical member.

[0001] This application is a Continuation-in-Part of co-pending U.S.patent application Ser. No. 09/099,858 filed Jun. 18, 1998.

BACKGROUND OF THE INVENTION

[0002] Inflatable seat belts have included perforated fabrics (U.S. Pat.No. 3,801,156). Other seat belts have included folded woven fabricbodies within a rupturable cover (U.S. Pat. Nos. 5,346,250 and5,383,713). Inflatable seat belts have been pleated and stitched for useprior to inflation reinforcing material (U.S. Pat. No. 3,866,940).

[0003] Prior inflatable seat belts have included decorative covers thathad little or no load bearing ability. Further, the attachment betweenthe inflatable sections and the non-inflatable sections lackedsufficient reinforcement to withstand the high loading occurring duringa crash.

SUMMARY OF THE INVENTION

[0004] Broadly the preferred embodiment of the present inventioncomprises a vehicle seat and seat belt system including two-part torsobelt section with an inflatable inner component inserted into andcoextensive with an outer component. The outer component comprises atubular webbing made of fabric or other suitable material havingstrength characteristics similar to conventional seat belting. Thetubular form of the outer component is formed by weaving two oppositeedges of the webbing with a frangible seam that is designed to rupturewhen the inflatable inner component is inflated. However, even when theouter component seam is ruptured, the webbing still continues to act asa conventional seat belt. It remains attached at both ends in a mannersimilar to the manner in which conventional seat belts are attached.

[0005] The inflatable inner component comprises an inflatable tube,bladder or other inflatable component positioned co-extensively withinthe tubular webbing of the outer component. The frangible seam orknitted catch cord of the outer component allows the inner inflatablecomponent, as it inflates, to exit the outer component through a ruptureopening in the tubular webbing during the period of vehicle decelerationpending a crash. A dynamic crash event occurs when the vehicle is inmotion when it encounters a crash or collision. A static crash eventoccurs when the vehicle is stationary when something else crashes intoor collides with it.

[0006] The expansion pressure and forces of the inflation of the innercomponent cause the frangible seam of the tubular webbing of the outercomponent to rupture due to the shearing of the catch cord. The innerinflatable component, when inflated, also acts in a similar manner tothe outer component, with both components acting in a manner similar toa conventional seat belt. That is to say that both the inflated innerinflatable component and the outer component are capable of bearing thetensile load impressed thereon by a passenger's deceleration in a crashevent.

[0007] The inner inflatable component, additionally, functionally actsas an air bag, to spread the load and cushion the passenger during thatcrash event. The combination of outer component and inner inflatablecomponent may also be used in a lap belt section of a seat belt, as wellas in the torso belt section.

[0008] The belt system may be used in combination with a structural seathaving a frame in which a belt enclosure and anchor are positionedbehind the occupant and secured to the seat frame. The enclosure housesthe torso belt section of the system, which includes the outer and innerinflatable components. An inflator is positioned within the innerinflatable component. The amount of belting withdrawn from the enclosuredepends on the size and/or shape of the occupant as he or she bucklesup. Alternatively, the belt enclosure and anchor may be mounted on otherportions of the vehicle including its frame.

[0009] These and other advantages are more fully explained in thefollowing drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In the drawings:

[0011]FIG. 1 is a perspective view of the vehicle seat with a beltsystem of the present invention;

[0012]FIG. 2 is the same view of FIG. 1 in which the belt system isbuckled up around the occupant;

[0013]FIG. 3 is a rear perspective view of the seat frame, rear beltenclosure and anchor mounted to the seat;

[0014]FIG. 4 is a broken-away perspective view of that portion of thebelt including an inflator which portion resides in the belt enclosure;

[0015]FIG. 4a is a sectional view taken along line 4 a-4 a of FIGS. 4and 7;

[0016]FIG. 4b is a sectional view taken along line 4 b-4 b of FIG. 2;

[0017]FIG. 5 is a perspective view of the seat of FIG. 1 with the torsosection of the belt system inflated;

[0018]FIG. 6 is a sectional view of the inflated torso belt section;

[0019]FIG. 6a is a view along line 6 a-6 a of FIG. 6;

[0020]FIG. 6b is a view along line 6 b-6 b of FIG. 6;

[0021]FIG. 6c is a sectional view similar to FIG. 6b after inflation;

[0022]FIG. 7 is a sectional view of the torso belt portion prior toactivation of the inflator;

[0023]FIG. 8 is an enlarged view of the torso belt with a tubular outercomponent and inner component readied for expansion by the inflator;

[0024]FIG. 9 is a perspective view of a portion of the fabric of theouter tubular belt component;

[0025]FIG. 10 is a plan view of a portion of the fabric of the outertubular belt component illustrating the frangible thread or catch cord;

[0026]FIG. 11 is a plan view of a portion of an alternative fabric ofthe outer belt component;

[0027]FIG. 12 is a perspective view of the alternative fabric; and

[0028]FIG. 13 is a perspective view of another embodiment wherein thebelt enclosure is mounted adjacent the seat on the vehicle frame.

DETAILED DESCRIPTION OF THE INVENTION

[0029] Referring to the Figs by the characters of reference there isillustrated a vehicle structural seat 20 having a seat portion 22, aback portion 24, an upper back portion 25, and a base portion 26. Thevehicle structural seat 20 is described in U.S. Pat. No. 5,851,055issued Dec. 22, 1998, to Donald J. Lewis entitled “InflatablePassenger-Size Adjustable Torso Belt System Including Enclosure Mountand Method of Passenger Restraint” and assigned to a common assignee.This patent is incorporated herein by reference.

[0030] Mounted to the seat 20 is a belt system 28 having an occupantrestraint belt 30 including a torso belt section 32 and a lap beltsection 34. The lap belt section 34 has a tongue connector 36 with abelt holding opening 38 and a tongue 40. The lap belt section 34 has, inits unbuckled mode, two ends with one end connected through a rear beltportion 44 to a rear retractor and payout anchor reel 48. The payoutanchor reel 48 is positioned behind the back portion 24 and upper backportion 25 on a seat frame 50 (FIG. 3).

[0031] The other end of the lap belt section 34 is adapted to beconnected to a side anchored buckle receiver 42 with the tongue 40 (FIG.1). The torso belt section 32 reciprocally moves in a belt guideenclosure 58 as the length of the rear belt portion 44 pays out andretracts back into rear retractor and payout anchor reel 48. The beltguide enclosure 58 includes a horizontal enclosure section 60 secured tothe seat frame 50 and an upper enclosure slot 56.

[0032] The torso belt section 32 includes the tandemly connected rearbelt portion 44, which changes direction as it passes around the guideD-ring 62 located within the horizontal enclosure section 60. The guideD-ring 62 is mounted to the seat frame 50. The torso belt section 32extends from a belt stitching or a means of attachment 52 adjacent aseat side reel anchor 54, upwardly alongside the occupant's torso intoan enclosure slot 56. The torso belt section 32 is attached to the rearbelt portion 44 by another stitching or a means of attachment 46. Therear belt portion 44 is preferably made of conventional seat beltwebbing.

[0033] An inflator 64 is held within the torso belt section 32 andwithin the belt guide enclosure 58 and moves along with the torso beltsection 32 as it reciprocates. The position of the inflator 64 in thebuckled-up mode therefore depends on the amount of the torso beltsection 32 utilized by the occupant as he or she buckles up; that amountvaries with the occupant's size and shape.

[0034] Turning now to FIGS. 4-6, the torso belt section 32 includes anouter tubular belt component 66 and an inner inflatable tubular beltcomponent 68 that is folded for storage within the outer belt component66. The diameter of the inner belt component 68, when inflated, istypically three to four times the width of the outer belt component 66when the outer belt component has been ruptured and spread out in themanner shown in FIGS. 6a and 6 b. In FIG. 6a, the outer belt componentis partially folded over itself after rupturing. A diameter to widthratio as high as five or six to one is acceptable. The outer beltcomponent 66 may be formed by weaving a cylindrical member, typicallyhaving an oval cross-section.

[0035] The inner belt component 68 as stored includes one or more folds68 a-68 h as illustrated in FIGS. 4-4 b. FIG. 4a illustrates a crosssection of torso belt section 32 within belt guide enclosure 58,including a cross section of inflator 64. FIG. 4b shows an uninflatedcross section of the torso belt section 32 across the occupant's torsoand an open passageway 70 extending longitudinally along the axis of thefolds of the inner belt component 68. This passageway 70 provides a flowpath for the gas output of the inflator 64 to the belt stitching 52.

[0036] The outer belt component 66 has a projection 72 on either side. Afrangible line 74 lies in one of the projections 72. Inflation of thetorso belt section 32, specifically inflation of inner belt component68, should be to a sufficient diameter and length to push the occupantback in his or her seat, but not so large so as to create a danger ofinjury. As a crash event loads the torso belt section 32, the load isshared by both the outer belt component 66 and the inner belt component68. An increasing amount of the load is transferred to the inner beltcomponent 68 as it becomes inflated.

[0037] Depending upon the size and shape of the seat occupant, partialinflation occurs in a portion of torso belt section 32, that iscontained in the inner wall 76 of the belt guide enclosure 58. Fullinflation of the torso belt section 32 that is contained within the beltguide enclosure 58 is restrained.

[0038] In the first and earliest phase of a crash, the inflator 64 isactuated to supply gases to the inner belt component 68 to flow alongthe passageway 70. The gases start to inflate the inner belt component68 for exerting pressure on the inner walls of outer belt component 66.When the pressure reaches a certain level the outer belt component 66ruptures along the frangible line 74 and the inner belt component 68starts to exit through the ruptured area 78 (FIG. 5). The frangible line74 extends longitudinally along a single edge of the outer beltcomponent 66 about at the location of one of the projections 72 (FIG.4a). It is a function of the frangible line 74 to provide length anddirection to the exiting of the inner belt component 68.

[0039] As the vehicle and occupant deceleration continues, the outerbelt component 66 begins to stretch due to load forces created by theoccupant. At the same time the inner belt component 68 begins topretension and foreshorten as it takes up an increasing portion of theload. In the next phase when the inflating inner belt component 68 hasdeployed further, it takes more of the load and the outer belt component66 carries less of the load. Finally, when the inner belt component 68is fully deployed, it assumes a significant share of the load. The innerbelt component 68 is preferably designed to be capable of handling fromabout 60% to as high as about 90% of the load. Since the outer tubularand inner inflatable tubular components 68, 66 share the crash load,each can be made of a thinner and lighter material than isconventionally used for vehicle seat belting. The inner belt component68 and the outer belt component 66 may be made of any suitable material.The preferred material is woven fabric such as from polyester or nylonfibers or threads. The fabric of the outer belt component 66 preferablyhas a tensile strength between 3,000 lbs. to 6,700 lbs. and anelongation of less than 10% under a tensile strength of 2,500 lbs. Afrangible warp fiber 80, located along the frangible line 74 has arelatively low denier of fifty to four hundred twenty.

[0040] Full inflation of the torso belt section 32 occurs between thebelt stitching 52 (FIG. 5) and the stitching 46. The inflation of theinner belt component 68 and its deployment outside outer belt component66 occurs between belt stitching 52 and the enclosure slot 56.

[0041]FIGS. 6, 6a, 6 b and 6 c show the inner belt component 68 deployedthrough the ruptured area 78 formed by the rupture of the outer beltcomponent 66. Limited inflation occurs within the belt guide enclosure58 using some of the amount of gas discharged by the inflator 64.However, the great majority of gases provided by the inflator 64 inflatethe portion of the inner belt component 68 for torso restraint.

[0042]FIG. 6c shows the operation of deployed inner inflatable beltcomponent 68 fully inflated and with the full stress of the deceleratingseat occupant imposed upon it. The outer belt component 66 is in a fullystretched out posture, after frangible line 74 has fully ruptured. Theinner belt component 68 is exerting restraint upon the occupant's torsoto arrest forward torso movement beyond the fully stretched out width ofruptured outer belt component 66. The shape of inflated inner beltcomponent 68, as shown in FIG. 6c, is changed from circular to ovalshaped by the forces required to arrest the occupant's forward torsomovement. In FIG. 5, the outer tubular component 66 is somewhatbanana-shaped due to the small elongation of the outer belt component.

[0043]FIG. 7 illustrates a portion of the torso belt portion 32 withinthe belt guide enclosure 58, including the inflator 64.

[0044]FIG. 8 is a sectional view of the portion of torso belt section 32that is within the belt guide enclosure 58, not shown, including theinflator 64. It is the inner wall 76 of the belt guide enclosure 58 thatpartially confines the inflation of the inner belt component 68,preventing the rupture of that portion of the frangible line 74 withinthe belt guide enclosure 58.

[0045]FIG. 9 shows a portion of a woven fabric 82 of the outer beltcomponent 66. The longitudinal fibers 82 and the cross fill fibers 84form a hollow tubular member. One method of making the hollow tubularmember is by weaving a tube with a longitudinal frangible warp fiber 80that comprises the frangible line 74 as discussed above. Thelongitudinal frangible wrap fiber 80 fails due to tension in the crossfill fibers 84. In this embodiment, the longitudinal frangible warpfiber 80 comprises the frangible line 74 as discussed above.

[0046]FIG. 10 in an enlarged view of the woven fabric 82 as shown inFIG. 9. Inflation causes the cross fill fibers 84 to tighten and pull onthe longitudinal frangible warp fiber 80, in a direction perpendicularto the longitudinal alignment of the frangible warp fiber 80. Thiscauses it to break or rupture, creating the longitudinal ruptured area78 as indicated in FIGS. 5 and 6. In the alternative, the frangible warpfiber 80 may be a woven or knitted catch cord having a lower denier thanthat in the remaining longitudinal fibers. The denier should be lowenough such that the catch cord breaks in shear when 10-20 psi stress isexerted on it.

[0047]FIGS. 11 and 12 show an alternative arrangement for providinginternal pressure induced rupture of the outer belt component 66. A seam86 appears as a longitudinal line is formed by pre-weakening the fiberwith, e.g., chemical etch, laser light, a hot knife, a hot wire, a waterjet, etc., to establish a weakened area for rupture or tear line in thefabric. In order to make the seam, the outer belt component 66 must beturned inside out. The line made as discussed above and then the outerbelt component must be turned inside out so that the seam is on theinside. Alternatively, fibers can be weakened by reduction of fibercross-section. The cross or fill fibers 84 are in a directionperpendicular to the longitudinal direction of the seam 86.

[0048] When initially installing the belt system 28 on the vehicle seat20, care is taken to see that the frangible line 74 is properlypositioned. It is important that when the belt system inflates, therupture area 78 is along the outside of the occupant away from theoccupant's body midline. The function of the frangible warp fiber 80 orthe catch cord is to direct and control the extent of the exit of theinflated inner belt component 68.

[0049] In the preferred embodiment, the outer belt component 66 is asingle piece structure woven on a needle and/or shuttle loom in such afashion as to split the sheds creating one continuous oval orcylindrical shape hollow structure closed by a woven and/or knittedcatch cord. The catch cord may be a No. 5 Mueller design. Of course theouter belt component 66 may be a flat piece of woven fabric that has itssides sewn or knitted together with the frangible warp fiber 80 beingthe thread.

[0050] Turning to FIG. 13, an alternative embodiment of the presentinvention is shown in which an occupant restraint belt 88 passes into anenclosure 90 positioned adjacent the vehicle structural seat 92. Theenclosure 90 is -attached to the vehicle “B” pillar 94. The enclosure 90includes an upper slot opening 96 and a vehicle frame-mounted beltretractor and payout anchor 98. The terms “frame-mounted” and “vehicleframe” as used herein include “unibody” construction where the vehiclebody and floor act as the structural frame of the vehicle, as well asvehicle construction that includes a separable distinct frame assembly.Also illustrated are the vehicle structural seat 92, the back portion100 and the seat side reel anchor 102. This embodiment lends itself toretrofitting vehicles that were originally manufactured and assembledwithout the present invention.

[0051] In operation of the occupant restraint belt 30, an occupant sitsin vehicle structural seat 20, pulls the tongue connector 36 over his orher lap, and inserts the tongue 40 in the buckle receiver 42 (FIG. 1).The torso belt section 32 including its rear belt portion 44 pays out ofthe rear retractor pay-out anchor reel 48 and the lap belt section 34pays out of the seat side reel anchor 54. The inflatable torso beltsection 32 which pays out of the rear retractor pay-out anchor reel 48exits guide enclosure slot 56, in upper seat back 25 (FIG. 2). Theoccupant restraint belt 30 is designed so that the inflator 64 and alength of the attached rear belt portion 44 remain in the belt guideenclosure 58, even when the largest occupant is being accommodated. Thearrangement of the belt guide enclosure 58 and the enclosure slot 56 aresuch that they function to maintain the inflator 64, at all times,within the belt guide enclosure 58.

[0052] In further operation of the system, during a crash event when thevehicle experiences rapid deceleration, a crash sensor (not shown)activates the inflator 64 which discharges gases into the passageway 70of the inner belt component 68. The rear retractor payout anchor reel 48and the seat side reel anchor 54 lock up preventing any additional beltpay out. Since the inflator 64 is located in belt guide enclosure 58behind vehicle structural seat 20 or, in the enclosure 90, the gasesfirst discharged from the inflator 64 expand inner belt component 68within the confines of the belt guide enclosure 58 or enclosure 90.Since the belt guide enclosure 58 restrains the inflation of the innerbelt component 68 expansion, it does not emerge from the outer beltcomponent 66 even if the outer belt component 66 develops a frangiblesplit due to internal gas pressures.

[0053] Once the torso belt section 32 in the belt guide enclosure 58 hasbeen inflated to the extent permissible, further discharged gasesinflate the torso belt section 32 outside the belt guide enclosure 58and adjacent the occupant's torso. When pressure in the torso beltsection 32 outside the belt guide enclosure 58 reaches a certain level,the frangible line 74 in the outer belt component 66 breaks, causing itto rupture to form the ruptured area 78. The rupture begins at theweakest point and then rapidly rupturing along the longitudinal lengthof the outer belt component 66 between the enclosure slot 56 and thebelt stitching 52. Where the preferred embodiment of the frangible line74 is utilized, the frangible warp fiber 80 preferably (but notnecessarily) varies in strength along its length with its weaker portionbeing at the lower torso end adjacent the belt stitching 52 remote fromthe area of occupant's head and enclosure slot 56. Such variation infiber strength causes emergence of the inner belt component 68preferably at the area just above belt stitching 52 prior to itsemergence at the area adjacent the occupant's head.

[0054] The variation in strength of the frangible warp fiber 80 alongits length can be effected by, for example, varying its thickness alongits length. During vehicle deceleration and phases of inflation of thetorso belt section 32, as previously described, the system functions todecelerate the occupant as follows:

[0055] 1. Under normal driving conditions, the outer belt component 66is in engagement with the occupant's torso resists and counteracts theoccupant's forward and lateral motion. The area (width times length) ofthe outer belt component 66 that is initially loaded by occupant'smovement, is an area equal to or substantially equal its area in contactwith the occupant prior to any inflation. Such an area is typically inthe range of about fifty to seventy square inches.

[0056] 2. Upon the onset of inflation of the inner belt component 68 andthe rupture of outer belt component 66, the outer belt component 66 isreduced slightly in tensile strength due to the ruptured area 78eliminating the complete radial integrity of the tubular structure. Asthe occupant is decelerated, the outer belt component 66 elongatessomewhat and narrows slightly, due to the ruptured area 78 eliminatingradial integrity of the tubular structure.

[0057] 3. As the outer belt component 66 elongates and narrows, theinner belt component 68 is expanding laterally as it is inflated causingit to shorten. Further, the inner belt component 68, as it shortens, issubjected to an increasing amount of load exerted by the occupant. Thisload can become greater than the load on the outer belt component 66which has been ruptured.

[0058] 4. By the time the inner belt component 68 is fully inflated andthe occupant deceleration is reaching a point where a maximum load isbeing placed on belt system 28, the inflated inner belt component 68serves as a substantial portion of the occupant restraint. The innerbelt component 68, made of fabric or material similar or identical tothat of the outer belt component 66, stretches as it is loaded. Thisstretching provides, in its inflated state, a cushioning and loadlimiting effect against the occupant's torso. The overall cushioningeffect is produced by the stretch of the fiber of both the inner beltcomponent 68 and the outer belt component 66, as well as the inflationgas in inner belt component 68. Upon full inflation, the overall area ofbelt system 28 in contact with the torso, including both the inflatedinner belt component 68 and the outer belt component 66, is typically inthe range of about 150-180 square inches. This may vary depending on thewidth of the webbing of the inner belt component 68 and the size and/orshape of the occupant. Typically, about one-third of the circumferenceof the inflated inner belt component 68, at a minimum, is in contactwith the occupant, as indicated in FIG. 6c. Both the outer tubularcomponent 66 and the inner belt component 68 are constructed so thatneither breaks or fails when loaded during operation of the belt system28 of the present invention. The belt components stretch or elongatewhen loaded but do not fail.

[0059] Advantages to the two-component occupant restraint belts 30, 80of the present invention are to eliminate the non-load-bearingdecorative cover. This is accomplished by the webbing of the outer beltcomponent 66 acting as a load bearing member as well as the outer cover.By implementation of the two-component system of the present invention,the load to the inner belt component 68 is reduced in comparison toknown systems where only the inflatable belt bears the load. Thus,because of the reduced load in the present invention, the inner beltcomponent 68 permits lighter weight (<6.0 oz/square yard), lower denier(≦210 denier), and reduced thickness (≦0.009″) fabrics may be used forthe inner belt component 68. Also, the webbing of outer belt component66 acts as reinforcement for the sewn attachment means, the beltstitching 52, of the inner belt component 68 to rear belt portion 44.

[0060] Because the yarn used in the manufacture of the webbing of theouter belt component is larger (500 to 1300 denier) than that of thefabric of inner belt component (≦210 denier), the webbing of the outerbelt component better resists the tearing load action to the stitching46 and the belt stitching 62, induced by the pressure created by theinflator 64 as it inflates the inner belt component, and also as thefull load is imposed upon occupant restraint belt 30 by the crash event.

[0061] The outer belt component 66 and the inner belt component 66 maybe designed to have relative resistance to further elongation as loadedso that the percent of tensile loading on the outer belt component,after rupturing and elongation, has a determined tensile strength rangewith a median range. Likewise and the percent tensile loading on thealready inflated inner belt component 68 may be designed to have adetermined tensile strength range with a median range. The combinationof the two median ranges should equal 100% of the design tensilestrength of occupant restraint belt 30. This is also the case for anypoint in time during the crash event; thus the combined medians shouldalways equal 100% of the design tensile strength for any point duringthe crash event, although the percentage, for each separate component 66and 68 of the overall 100% may vary as the crash event proceeds frombeginning to end; from the initial deceleration to maximum loading.

[0062] Since both outer belt component 66 and inner belt component 68,in combination serve to carry the loads imposed during deceleration, thematerial of each separate component can be made thinner and lighter thanthe material used to produce conventional seat belts. Inflation ratesand amounts and the extent of inflation of inner belt component 68 maybe varied by varying the size, thickness and weight of both inner beltcomponent and outer belt component 66, and by selecting the inflator 64to be of varying type, size and output. While it is preferred that outerbelt component carry most of the initial load prior to its rupturecaused by inflation of inner belt component 68, other load sharingbetween such components may be provided by design. Upon inflation andrupture, it is preferred that the inner belt component 68 takesincreasingly more and more of the load as the crash event continues frominitiation to conclusion. Upon the maximum load being applied during thecrash, it is preferred that inflated inner belt component 68 carry asignificant share, in some cases over half of such load and be designcapable of carrying up to ninety per cent (90%) of such load.

[0063] When occupant restraint belt 30 is in normal use with theoccupant buckled up, the torso belt section 32 visible to the occupanthas an appearance similar to that of a conventional vehicle seat belttorso belt section.

[0064] The outer belt component 66 preferably has the physicalproperties of:

[0065] (1) tensile strength of 3,000-6,7000 lbs.;

[0066] (2) elongation of 7-10% at 2,500 lbs.; and

[0067] (3) thickness of 0.025-0.060 inches, all similar to conventionalseat belt webbing.

[0068] However, any suitable material can be used provided it canwithstand the initial loads, until inner belt component 68 takes up theload burden upon inflation, and provided it is readily scorable, or canotherwise be weakened to form the frangible line 74, to accomplishproper rupture during inflation as discussed above. The outer beltcomponent 66 preferably includes as a frangible line 74 a relatively lowdenier (50 to 420) woven frangible warp fiber 80. The cross or fillfibers 82, positioned at approximately right angles to the warp fibersin the fabric cause the frangible warp fiber 80 to fail when inflationoccurs by the fill fibers 82 pulling laterally on the frangible warpfiber 80.

[0069] The webbing of the outer belt component 66 ranges in thicknessfrom 0.035 inches to 0.055 inches and ranges in width from 1.875 inchesto 2.5 inches when doubled over to form a tube. That webbing ispreferably an uncoated woven polyester hollow webbing. Polyester waschosen as the preferred material for its low elongation and lowflammability properties.

[0070] The inner tubular component 68 is preferably constructed of a 210denier or less nylon or polyester woven fabric coated for air retentionpurposes, preferably with either a thermal plastic polyurethane (forease of heat sealing) or silicone coating. Preferred fabriccharacteristics and properties are as follows: Weave Pattern: Plain, 2:1Twill, Oxford or Basket Weight (oz./yd²⁾: 4.5-6.0 Thickness (inches):0.006-0.009 Tensile Strength (psi): 220-280 (Hoop Direction) TensileStrength (psi): 275-325 (Longitudinal Direction)

[0071] The diameter of the inner tubular component 68 at about 10 psiginflation pressure is typically about six inches. However, it may rangein diameter from about four inches to about ten inches depending uponthe size and/or shape of the occupant.

[0072] The expansion of inner belt component 68 causes the portion ofouter belt component 66 positioned in the belt guide enclosure 58 toengage the inner wall 76 over a distance between the inflator 64 and theenclosure slot 56, 96. This engagement of the inner wall 76 caused byinflation pressure and friction assists in transferring the load tovehicle structural seat 20, 92. The load is distributed diagonallyacross seat frame 50 substantially over the length of belt guideenclosure 58 as shown in FIG. 3.

[0073] The outer belt component 66 remains in contact with the occupantduring operation with the inflated inner belt component 68 deployingaway from and substantially out of contact with the occupant. The outerbelt component 66 provides an insulation layer between the occupant andhot gases that may be expelled from the inflator 64 and utilized toinflate inner belt component 68.

[0074] Finally, the dual component belt of the present invention may beutilized in the lap belt section or in both the torso and lap beltsections. A second inflator may be positioned to serve the lap beltsection but is not necessary if a run-through D-buckle tongue isemployed.

What is claimed is:
 1. A seat belt system, adaptable to a vehicle and avehicle seat, comprising: a rear retractor and pay-out anchor mounted tothe vehicle seat; a belt guide enclosure mounted to the vehicle seatadjacent to and extending from said rear retractor and pay-out anchormeans; a belt webbing connected at one end to and extending from saidrear retractor and pay-out anchor to and within said belt guideenclosure, said rear retractor and pay-out is adapted to pay out andretract said belt webbing; an inflator having a first end connected tothe other end of said belt webbing, said inflator being confined withinsaid belt guide enclosure and movable therein co-extensively with thepay-out and retraction of said belt webbing; an inner inflatable tubularbelt component, having a first end attached to said other end of saidbelt webbing and surrounding and encompassing said inflator andextending co-extensively from said belt webbing through said belt guideenclosure and beyond the end of said belt guide enclosure which is mostremote from the location of said rear retractor and pay-out anchor, saidinner inflatable tubular belt component being movable to retract andpay-out co-extensively with the movement of said inflator and said beltwebbing; an outer tubular belt component having a first end attached tosaid belt webbing at the same point as said first end of said innerinflatable tubular belt component, said outer tubular belt componentsurrounds and encompasses said inner inflatable tubular belt componentwhen said inner tubular belt component is not inflated, said outertubular belt component includes a frangible line extendinglongitudinally along a side edge of said outer tubular belt component,said frangible line functions to rupture along its length and transformat least a portion of outer tubular belt component into non-tubularwebbing means when said inner inflatable tubular belt component isinflated by said inflator; a connector attached a second end of saidinner tubular belt component and a second end of said outer tubular beltcomponent, both of said second ends which are attached to said connectorwith the same attachment, said connector functions to removably connectboth of said second ends to the vehicle seat, the combination of saidinner tubular belt component, said outer tubular belt component and saidconnector comprises a torso belt section; and a lap belt sectionattached at a first end to said connector and attached at a second endto a side retractor and pay-out anchor mounted adjacent the side of thevehicle seat such that said side retractor and pay-out anchor isoperable to pay-out and retract said lap belt section; wherein saidouter tubular belt component and said inner inflatable tubular beltcomponent both bear the load of restraining an occupant of the vehicleseat during a crash event as well as during non-crash event of thevehicle.
 2. A seat belt system, adaptable to a vehicle and a vehicleseat, comprising: a retractor and pay-out anchor mounted to the frame ofthe vehicle adjacent the vehicle seat; a belt guide enclosure mountedadjacent to the vehicle seat extending from said retractor and pay-outanchor; a belt webbing connected at one end and extending from saidretractor and pay-out anchor to and within said belt guide enclosuresaid retractor and pay-out anchor operates to pay-out and retract saidbelt webbing; an inflator having a first end connected to the other endof said belt webbing, said inflator being confined within said beltguide enclosure and movable within the confines of said belt guideenclosure co-extensively with the retraction and pay-out of said beltwebbing to and from said rear retractor and pay-out anchor; an innerinflatable tubular belt component having a first end attached to saidother end of said belt webbing, said inner inflatable tubular beltcomponent surrounds and encompasses said inflator, and extendsco-extensively from said belt webbing through said belt guide enclosurebeyond the end of said belt guide enclosure that is most remote from thelocation of said retractor and pay-out anchor, said inner inflatabletubular belt component being movable to retract and pay-outco-extensively with the movement of said inflator and said belt webbing;an outer tubular belt component having a first end attached to said beltwebbing at the same point as said first end of said inner tubular beltcomponent to said belt webbing, said outer tubular belt componentsurrounds and encompasses said inner tubular belt component when saidinner inflatable tubular belt component is not inflated, said outertubular belt component includes a frangible line extendinglongitudinally along a side edge of said outer tubular belt component,said frangible line functions to rupture along its length and transformat least a portion of outer tubular belt component into a non-tubularwebbing when said inner tubular belt component is inflated by saidinflator; a connector attached to a second end of said inner tubularbelt component and to a second end of said outer tubular belt component,both of said second ends being attached to said connector with the sameattachment, said connector functions to removably attach both of saidsecond ends to the vehicle seat, the combination of said inner tubularbelt component, said outer tubular belt component and said connectorcomprises a torso belt section; and a lap belt section attached at afirst end to said connector and attached at a second end to a sideretractor and pay-out anchor mounted adjacent the side of the vehicleseat such that said side retractor and pay-out anchor operates topay-out and retract said lap belt section, wherein said outer tubularbelt component and said inner tubular belt component both bear the loadof restraining an occupant of the vehicle seat during a crash event aswell as during a non-crash event of the vehicle.
 3. In a vehicle havinga seat for a human occupant, a belt restraint system comprising: a beltmember for restraining the occupant during vehicle deceleration andother movement of the occupant relative to the seat, said belt memberbeing loaded by forces imposed by the occupant during the vehicledeceleration and other movement of the occupant relative to the seat;said belt member including an outer belt component and an inner beltcomponent, the respective ends of said components being connected to oneanother at spaced-apart locations, said belt components each share asubstantial portion of the load forces on said belt member imposed bythe occupant; a portion of said outer belt component being frangible tocreate an opening when said portion is stressed; an inflator incommunication with said inner belt component for inflating saidcomponent upon the vehicle encountering a crash event; whereby when saidinflator inflates said inner belt component, said outer belt componentruptures at said frangible portion due to inflation stress creating anopening and allowing said inner belt component to exit said opening forproviding an inflated belt section for occupant deceleration cushioning.4. The belt restraint system of claim 3 wherein said belt membercomprises a torso restraining member.
 5. The belt restraint system ofclaim 3 wherein said belt member comprises a lap belt.
 6. The beltrestraint system of claim 3 wherein during inflation of said inner beltcomponent, said inner belt component assumes increasingly more of saidload forces of said deceleration of the occupant, while said outer beltcomponent correspondingly assumes decreasingly less of said load forces.7. The belt restraint system of claim 3 wherein said deceleration of theoccupant extends over a period of time including a first phase whereinrupture occurs, a second phase of inner belt component inflation and afinal phase wherein the inner belt component is fully inflated, and theshare of the load forces of said outer tubular belt component beingreduced during said second phase and into said final phase, and saidinflated inner belt component withstands progressively more of said loadforces during said second phase and into said final phase.
 8. In avehicle having a seat for an occupant, a belt restraint systemcomprising: a belt member restraining the occupant during vehicledeceleration and other movement of the occupant relative to the seat,said belt member being loaded by forces imposed by the occupant; saidbelt member including an inflatable torso belt section anchored betweena first anchor adjacent the seat and a second anchor behind the seat; aninflator in communications with said torso belt section; said inflatabletorso belt section including an outer belt component and an inner beltcomponent: (i) said components being connected to one another atspaced-apart locations along said torso belt section; and (ii) saidcomponents sharing said load forces of said torso belt member duringvehicle deceleration; and said outer belt component having a frangibleportion that functions to create an opening when said frangible portionis stressed, said opening through which said inner belt componentemerges upon its inflation; whereby said inflator inflates said innerbelt component upon the vehicle encountering a crash event, causing saidfrangible portion of said outer component to rupture creating saidopening allowing said inner belt component to emerge from said openingto provide an inflated torso belt section.
 9. The belt restraint systemof claim 8 wherein said belt member further comprises a lap belt. 10.The belt restraint system of claim 8 additionally including a belt guideenclosure between the occupant and said second anchor.
 11. The beltrestraint system of claim 10 wherein said inflator is positioned withinsaid inflatable torso belt section and said inflator and a portion ofsaid inflatable torso belt section are located within said belt guideenclosure.
 12. The belt restraint system of claim 8 wherein said outerbelt component comprises a woven fabric with a plurality of longitudinalwarp threads and in which said frangible portion is a warp thread thatis weaker than the other of said plurality of longitudinal warp threads.13. The belt restraint system of claim 8 wherein said outer beltcomponent comprises a woven fabric with a plurality of longitudinal warpthreads and in which said frangible portion is a knitted catch cord thatis weaker than the other of said plurality of longitudinal warp threads.14. The belt restraint system of claim 12 wherein said weaker threadextends at least across the torso of the occupant to adjacent said firstanchor and wherein said weaker thread of said frangible portion is evenweaker at the end adjacent said first anchor than at its opposite end.15. The belt restraint system of claim 12 additionally including a beltguide enclosure between the occupant and said second anchor and whereinsaid vehicle has a frame and wherein said belt guide enclosure issecured to said vehicle frame.
 16. A method of restraining an occupantin a seat in a vehicle comprising: providing a woven cylindrical outertubular belt member anchored at two anchor locations within the vehicle,with the first of said anchors being located adjacent the seat and thesecond of said anchors being located at a remote location within thevehicle, said woven cylindrical outer tubular belt member adapted to beloaded by the forces required to decelerate the occupant upondeceleration of the vehicle and by other movements of the occupantrelative to the seat; locating within said woven cylindrical outertubular belt member an inner inflatable tubular belt member, said innerinflatable tubular belt member having two ends and a middle portion withsaid middle portion extending across at least a portion of the occupantand the two ends of said inner inflatable tubular belt member beingsecured, respectively, to the corresponding ends of said wovencylindrical outer tubular belt member; providing as part of said wovencylindrical outer tubular belt member a frangible portion rupturableupon inflation of said inner inflatable tubular belt member so as topermit said inner inflatable tubular a belt member to exit said wovencylindrical outer tubular belt member, said woven cylindrical outertubular belt member and inner tubular belt member substantially sharethe occupant deceleration load during vehicle deceleration upon thevehicle encountering a crash event; providing an inflator; and locatingsaid inflator in communication with said inner inflatable tubular beltmember so that upon a crash event caused deceleration of the vehicle,said inflator inflates said inner inflatable tubular belt member causingit to exit said woven cylindrical outer tubular belt member to assist indecelerating the occupant as the vehicle decelerates.
 17. The method ofrestraining an occupant of claim 16 wherein said woven cylindrical outertubular belt member and said inner inflatable tubular belt memberextends diagonally across the torso of the occupant.
 18. The method ofrestraining an occupant of claim 16 wherein said woven cylindrical outertubular belt member and said inner inflatable tubular belt memberextends across the lap of the occupant.
 19. The method of restraining anoccupant of claim 16 including the step of providing a belt guideenclosure between the occupant and said remote anchor, said wovencylindrical outer tubular belt member and said inner inflatable tubularbelt member simultaneously reciprocating from and within said belt guideenclosure.
 20. The method of restraining an occupant of claim 19 whereinsaid inflator is located within said inner inflatable tubular beltmember and within said belt guide enclosure.
 21. The method ofrestraining an occupant of claim 16 wherein said woven cylindrical outertubular belt member and said inner inflatable tubular belt member sharethe load caused by deceleration of the occupant upon the vehicleencountering a dynamic crash event, with said woven cylindrical outertubular belt member ultimately carrying a lesser load following itsrupture, during the course of dynamic crash event caused vehicledeceleration, and said inner inflatable tubular belt member ultimatelycarrying a greater load after complete inflation.
 22. The method ofclaim 16 wherein said woven cylindrical outer tubular belt member andsaid inner inflatable tubular belt member have varying relativeresistance to further elongation as loaded during the course ofdeceleration of the occupant upon the vehicle encountering a crashevent, such that the percentage of overall tensile loading on said wovencylindrical outer tubular belt member and the percentage of overalltensile loading on said inner inflatable tubular belt member varyconstantly during the course of deceleration wherein at all pointsduring said deceleration of the occupant, from initiation totermination, said percentages add up to one hundred percent.
 23. Themethod of claim 16 whereby said woven cylindrical outer tubular beltmember and said inner inflatable tubular belt member have relativeresistance to further elongation, as loaded by deceleration of theoccupant upon the vehicle encountering a crash event, with theresistance to further elongation of said woven cylindrical outer tubularbelt member being lessened upon its rupture.
 24. The method of claim 16wherein said woven cylindrical outer tubular belt member comprisesfabric and said rupturable portion comprises a frangible warp fiber insaid fabric.
 25. The method of claim 16 wherein said woven cylindricalouter tubular belt member comprises fabric and said rupturable portioncomprises a catch cord extending longitudinally in said fabric.
 26. Themethod of claim 16 wherein said deceleration of the occupant, upon thevehicle encountering a crash event, extends over a period of timeincluding a first phase during which rupture occurs, a second phase ofinner component inflation and a final phase in which said innercomponent is fully inflated, and the share of the occupant decelerationload on said woven cylindrical outer tubular belt component isprogressively reduced during said second phase, from immediatelyfollowing said first phase during which said rupture occurs, and intosaid final phase, and said inner inflatable tubular belt componentwithstands progressively more of a share of said load during said secondphase and into said final phase.
 27. The method of claim 26 whereby theshare of said load of said deceleration of the occupant imposed uponsaid woven cylindrical outer tubular belt component is substantiallyreduced at the end of said first phase, and in which said innerinflatable tubular belt component, when inflated, withstands anincreased amount of said load in said final phase.
 28. The method ofclaim 16 wherein there is a period of inflation of said inner inflatabletubular belt member as it exits from within said woven cylindrical outertubular belt component, and during said period of inflation, said innerinflatable tubular belt member bears an increasing amount of the load ofdeceleration of the occupant upon the vehicle encountering a crashevent, taking some of said load from said woven cylindrical outertubular belt component.